SpaceShipOne is one of more than 20 craft vying for the $10m (£5.7m) Ansari X-Prize, which rewards the first team to send a non-government, three-person craft over 100km (62 miles) into space, and repeat the feat in the same carrier inside two weeks.

The Virgin boss was flanked at Monday's announcement by Rutan, who has already collaborated with Sir Richard on Virgin GlobalFlyer, a jet plane designed to fly non-stop around the world without refuelling.

THE VIRGIN SPACESHIP

The vehicle will have room for five passengers

A week's pre-flight training will be required

Three-hour trip; three minutes of weightlessness

Flights to leave from Mojave Desert, initially

Tickets to cost about £100,000, perhaps less

"Virgin has been in talks with Paul Allen and Burt throughout this year and in the early hours of Saturday morning signed a historic deal to license SpaceShipOne's technology to build the world's first private spaceship to go into commercial operating service," said Sir Richard, who founded the Virgin Group of companies.

Commentators said it was a logical next step for someone to come in and move the SpaceShipOne technology into the commercial flight business.

David Ashford, director of UK-based Bristol Spaceplanes Limited, another X-Prize contender, said space was finally being opened up for ordinary people.

"The price will come down - there's no doubt about that," he told BBC News Online.

"The X-Prize has succeeded in doing what it set out to do. The original idea was to break the mould of thinking - to break Nasa's monopoly on space policy. Space tourism should have happened many years ago."

Design, build and testing

The deal with Mojave Aerospace Ventures allows Sir Richard to use the SpaceShipOne technology. He will now have five bigger versions of the current vehicle built. The Virgin SpaceShip (VSS) will carry five passengers compared with the two-passenger capacity offered by SpaceShipOne.

The final design for the maiden ship, the VSS Enterprise, should be signed off in 2005.

Branson and Rutan are involved with Steve Fossett in the Virgin GlobalFlyer project

The vehicle will then have to be built and tested before beginning a scheduled space service.

"Every passenger will have a spectacular view; they will have considerable windows and luxurious seats," Sir Richard said.

"Initially, they will take off from the Mojave Desert near Los Angeles. It will be a three-hour journey. Passengers would have about a week's training prior to taking off."

The Virgin Group has interests in a range of businesses, including trains, finance, soft drinks, music, mobile phones, holidays, and cars.

Globally, Sir Richard is probably best known for his Virgin Atlantic airline and for his speedboat and ballooning adventures.

He said many of the group's existing pilots would be in line to take the controls of a VSS vehicle after the necessary training.